Cluster headache: intense one-sided head pain

There is a type of headache that comes on suddenly, is extremely intense, and recurs in a near-predictable pattern. A characteristic feature is that the pain is localised around a single eye, with associated symptoms appearing on the same side of the face.

This is known as cluster headache, which produces severe episodes of pain, most commonly around or behind one eye. During an attack, symptoms such as tearing, eye redness, nasal congestion or discharge, and drooping of the eyelid may occur — all on the same side of the face affected by the pain. Attacks typically occur in series — sometimes several times a day — over a period of weeks or months, followed by intervals during which symptoms disappear entirely.

Because the pain comes on very rapidly, any treatment administered during an attack must work equally quickly. Oxygen therapy, along with certain medications given by injection or nasal spray, can halt attacks. Alongside this, preventive treatment aims to reduce the number of attacks during an active cluster period. A neurological assessment is important to distinguish this type of headache from migraine or other conditions that may cause severe head pain.